so far, Mr. Biden has failed to deliver on his pledge to raise the corporate income tax rate to 28 percent from 21 percent, partly undoing a rate cut signed by President Donald J. Trump, which lowered the rate from 35 percent. Mr. Biden announced a new plan to unite Democrats around that agenda on Thursday, shortly before leaving for Rome, but it did not include an increase in the corporate rate.

Instead, his framework contained two new 15 percent minimum taxes: one on the income American companies earn abroad, and one on the profits that large corporations report to their shareholders.